The present invention relates generally to the art of designing and manufacturing welding-type system. More specifically, it relates to designing and manufacturing different welding-type systems used in a variety of processes and having a variety of outputs.
Welding-type power supplies or systems are made for a variety of processes, such as stick, TIG, MIG, pulse, sub-arc, heating, cutting, and the maximum output power or current can be anywhere from one hundred or less amps, to five hundred or more. The maximum output of a particular welding-type system is chosen for the process and/or commercial market for which it is intended.
In the prior art, a welding power supply has been designed for a particular output, and the power circuitry, controller, output circuitry, etc., are designed with the maximum output power in mind. Thus, a 100 amp system might be considerable different from a 200 amp machine, which is different from a 300 amp machine and so forth.
Unfortunately, designing a system from the ground up requires extensive engineering for each system. Sometimes, in an effort to reduce the attending engineering costs, a power supply is scaled up for a higher output by increasing switch capacities, or placing switches in parallel. However, there are limits to this sort of scaling up, and it gets ever more costly for components to tolerate ever greater currents.
Occasionally, a system has had its output increased by placing two power supplies in parallel. While this allows easier design of a system, it is limited in its applications to systems having twice the maximum output of the base system. Also, the input circuits were limited to a particular type of input and the two-supply machine was capable of working off one particular utility source. Thus, the use of the two supplies to design a system was of rather limited application.
Accordingly, a method of designing power supplies that allows the use of commonly engineered circuitry that can produce maximum output power of a wide range is desired. Also, the method will preferably be used to design systems for a variety of type of input and output power and used in a variety of processes.
According to a first aspect of the invention, a method of manufacturing a plurality of welding-type systems that are each suitable for at least one of a plurality of processes includes connecting a number xe2x80x9cNxe2x80x9d power modules in parallel. Each power module produces a module output power, and has a maximum output power of at least Ppm. Each power module has a common preregulator that receives any input voltage over a range of input voltages and/or power factor corrects the input, and they include a converter circuit connected to the preregulator. The number N is determined by determining a desired maximum system power Pd1 for a first particular system, and by dividing Ppm into Pd1.
According to a second aspect of the invention a welding-type system suitable for at least one process having a desired maximum system power of Pd, includes N power modules connected in parallel. The parallel connection has an input and an output. N is an integer equal to Pd/Ppm rounded up, and Ppm is an output power of each power module. Each module has a preregulator capable of receiving any input voltage over a range of input voltages. A system output is connected to the output.
According to one embodiment a second power module produces output power of at least Ppm and includes the common preregulator. It also includes a second converter circuit connected to the preregulator. A desired maximum system power Pd2 for a second particular system is determined, and Ppm is divided into it to obtain a number N2. N2 second power modules are connected in parallel.
According to other embodiments the output circuit includes an inverter that inverts dc power, and/or a switched snubber.
The preregulator that includes an SVT and/or an SCT circuit in another embodiment.
A single user interface is operatively connected to the N power modules in yet another embodiment.
The output circuit converts the output to an ac, dc, cc, and/or cv welding-type output in various embodiments.
According to a third aspect of the invention a method of designing a plurality of welding-type systems includes designing a common power circuit capable of receiving an input and producing a maximum output dc power of at least Ppm. Also, it includes determining a desired maximum system power Pd for each of the plurality of systems. The number of power modules that will collectively produce the output power Pd for each of the plurality of systems is determined. The type of output power desired for each particular system is determined and at least one output circuit that converts the output to the type of power desired is designed.
Yet another aspect of the invention is a welding-type system suitable for at least one process having a desired maximum system power of Pd, that includes N power modules connected in parallel. N is an integer equal to Pd/Ppm rounded up to the nearest integer, where Ppm is an output power of each power module. Each power module has a preregulator having an SCT and SVT circuit.
According to one alternative the power module is designed to receive any input voltage over a range of input voltages.
According to another aspect of the invention a welding-type system suitable for at least one process has a desired maximum system power of Pd. The system includes N first power modules connected in parallel with M second power modules. The parallel connection has an input and an output, and the total power output is greater than Pd. Each first and second power module has a preregulator capable of receiving any input voltage over a range of input voltages.
Other principal features and advantages of the invention will become apparent to those skilled in the art upon review of the following drawings, the detailed description and the appended claims.